Switching actuator for a concrete vibrating tool



p 9, 1969 A. PGTTGENS 3,466,014

SWITCHING ACTUATOR FOR A CONCRETE VIBRATING TOOL Filed Nov. 29, 1966 Prior Art h a 1 I |f )i l pz zz 1 Fig. I

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In ventor: Anton ps' ms MQMQM United States Patent 3,466,014 SWITCHING ACTUATOR FOR A CONCRETE VIBRATING TOOL Anton Piittgens, 28 Robensstrasse 51, Aachen, Germany Filed Nov. 29, 1966, Ser. No. 597,728 Claims priority, application Germany, Dec. 6, 1965,

Int. Cl. H01h 1/08, 29/06 US. Cl. 259-1 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to concrete vibrating tools, and in particular to an improved switching arrangement in vibrating tools having a flexible hose serving as a handle, and a casing for an electrical cable leading from an electrical connection to an electrical motor disposed within the vibrating tool.

Known concrete vibrating tools generally comprise a relatively long flexible tube or hose which also encases an electrical cable supplying power for the motor which drives the tool. The concrete vibrating tool is connected to one end of this hose, and an electrical switch is provided at the other end of the hose to provide an electrical connection between the motor within the tool and an external power source. In the operation of the known concrete vibrating tools, at least two operators must be employed; one to operate the tool itself, and another to operate the electrical on-off switch. The need for two operators in the use of known concrete vibrating tools is brought about by the fact that the vibrating tool may only be operated in concrete for a limited period of time, as the concrete would tend to disintegrate if the vibrating tool is used for a longer period of time, and the tool would wear out too rapidly. On the other hand, the concrete vibrating tool cannot be left in a switched on position, after the tool has been removed from the concrete, because the drive motor would burn out in a relatively short time. If, for example, only one operator is employed to handle one of the known concrete vibrating tools, he would have to remove the tool from the concrete, and then walk over to the switch location to turn off the vibrating tool. To begin a new operation, the operator would have to switch on the tool, and walk back to the tool to insert the tool into the concrete. It is quite apparent that the manner of operation of the known tools as described above is complicated, time consuming and, therefore, nneconomical.

Another disadvantage in known concrete vibrating tools is the requirement of unwieldy switches which often become tangled in iron frames during construction involving iron concrete. Usually the on-off switch used with the known concrete vibration tool must be positioned approximately 15-20 feet away from the concrete vibrating tool since the vibrating tool must, in some cases, be inserted deep into concrete such as in the construction of pillars. If the switch were located close to the vibrating tool, the switch would very likely become tangled in the concrete casing and may be torn loose from the tool, thus damaging the tool and rendering it inoperative. Furthermore, the switch may also be rendered inoperative due to heavy soiling, if the switch were located close to the tool.

It is, therefore, a general object of this invention to overcome the above-mentioned shortcomings of the known concrete vibrating tools, by providing a concrete vibrating tool which may be easily operated by a single operator, without any of the above-mentioned shortcomings.

It is a further object of this invention to provide an improved on-ff switching arrangement in a concrete vibrating tool, wherein simplified and trouble free operation of the tool is achieved,

It is yet another object of this invention to provide a concrete vibrating tool which has a switch located in the vicinity of the hose where the hose is gripped by the operator.

In accordance with certain features of this invention, the switch is located within the hose of the tool and is actuated by an actuating member which is also mounted in the hose, and which operates when the hose is placed in a reclining position, to thereby actuate the drive motor of the tool. Hence, the actuating of the motor depends essentially on the inclined position of the hose.

In a preferred embodiment of this invention, a mercury switch is provided within the hose, wherein the mercury forms the actuating member. As soon as the rear end of the hose, which is directed to the power source, is lifted, the mercury within the switch is brought into contact with the stationary contacts of the switch, to actuate the motor and the tool. In order to avoid unintentional actuation of the tool switch, the hollow chamber in which the mercury is disposed may be arranged in the form of a conical chamber having its wider portion disposed in the opposite direction of the tool. This wider portion of the conical chamber receives the mercury during the inoperative position of the tool.

Further advantages and details of the present invention will become more apparent from the following detailed description of one embodiment of the invention, considered together with the appended drawings in which:

FIG. 1 is a schematic view of a prior art concrete vibrating tool;

FIG. 2 is a schematic view of a concrete vibrating tool according to this invention; and

FIG. 3 is an enlarged sectional view of a switch in accordance with the invention.

With reference to the drawings, with particular reference to FIG. 1, there is shown a conventional concrete vibrating tool which comprises a cylindrical housing 1 in which a conventional electric motor 2 is disposed. A flywheel 3 is mounted on a shaft 14 of motor 2 and a flexible tubing or hose 4, which serves as a handle, is secured to housing 1. Hose 4 also serves as a casing for a cable 7. On the rear end of hose 4, an electric switch 5 is provided which connects cable 7 to a conventional threephase power source (not shown). The distance between the concrete vibrating tool and the switch is generally 15 to 20 feet, so that usually two operators are required, one for handling the tool and the other for actuating and turning 015? the switch.

FIG. 2 illustrates a concrete vibrating device in accordance with the present invention. Elements shown in FIG, 2, similar to those shown in FIG. 1, are identified by the same reference characters as indicated in FIG. 1. As can be seen in FIG. 2, on-ofi switch 6 is located in the portion of the hose 4 which is nearest the tool housing 1. In other words, the switch 6 is located at the portion of the concrete vibrator tool which would be gripped by the operator during the operation of the tool. Switch 6 is completely enclosed by the hose 4, so that it is completely protected from dampness, dirt or other adverse external factors which would tend to damage the switch. Furthermore, since switch 6 is located within hose 4, it cannot become tangled within the iron casing, should the vibrating tool be inserted into a pillar.

FIG. 3 is an enlarged section view of the switch 6 in accordance with the invention. A three-phase power cable 7 is embedded in hose 4 and connected to a suitable AC. power source (not shown). Two conductors 15, 16 of cable 7 are permanently connected to phase conductors 8 by means of conductors 17 and 18 respectively, which are in turn connected to motor 2. Two other conductors 19, 20 of cable 7 terminate at a pair of contacts 9 which extend into a conically shaped hollow chamber 10 formed within a switch housing 11. Conductor 20 is also connected by means of a conductor 21 with a phase conductor 12 which leads to motor 2. As can be seen in FIG. 3, the conical hollow chamber 10 expands in the direction of the power source so that the wider end of the conical chamber is away from the housing 1, A quantity of mercury 13 is placed within hollow chamber 10. Due to the gravitational force exerted on mercury 13, the mercury will always stay in the deepest location of hollow chamber 10 when hose 4 is in the horizontal position shown in FIG. 3. Whenever hose 4 is lifted away from its horizontal position, that is, when the concrete vibrating tool is inserted into the concrete, the mercury 13 will move under the force of gravity to engage contacts 9 to complete the electric circuit between the power source and electric motor 2. In this manner motor 2 is automatically actuated. As soon as the operator removes the tool from the concrete and inclines the hose rearwardly, or places the tool on the floor in a horizontal position, the mercury 13 will flow back into hollow chamber 10, as shown in FIG. 3, to automatically interrupt the circuit between the power source and motor 2.

It is also within the scope of this invention for the hollow chamber 10 to be cylindrical instead of conical. In this form, the cylindrical chamber would be provided with a suitably located annular recess for receiving the mercury 13 when the tool is in the horizontal or reclining position.

It is also within the scope of this invention for the hollow chomber 10 to be cylindrical instead of conical. In this torm, the cylindrical chamber would be provided with a suitably located annular recess for receiving the mercury 13 when the tool is in the horizontal or reclining position.

It is also within the scope of this invention that other suitable switches may be used which would operate on the inclined position of hose 4 during the operating of the tool in the manner described above. For instance, switches which are provided with a movable ball, a gliding contact pin, or the like may be utilized for this purpose.

It will also be appreciated that other modifications to the disclosed embodiment will occur to those skilled in the art. It is, therefore, intended in the appended claims to cover all such modifications that fall within the true spirit and scope of the invention.

What is claimed is:

1. A concrete vibrating means for use by a single operator comprising:

a conventional vibrating tool, having a cylindrical housing, with an electrical motor disposed therein for driving a flywheel,

a long flexible hose having one end connected to said housing,

a plurality of electrical cables disposed within said hose for coupling an electrical power source to said motor, and

an electrical switch actuating means comprising a conically shaped hollow chamber contained within said hose portion, a set of contacts disposed within said hollow chamber, said contacts being directed away from the wider portion of said concially shaped hollow chamber, and a quantity of mercury arranged for liquid movement within said chamber for closing across said contacts, said quantity being stored in said Wire portion and remote of said contacts when the axis of said chamber is in a substantialy horizontal position, said switch means being positioned at a location remote from said vibrating tool and forming a connection between said motor and said electrical power source in response to the inclination of said hose portion containing said switch actuating means.

2. The concrete vibrating means according to claim 1 wherein said hollow chamber includes an annular recess positioned remote of said contacts for receiving said quantity of mercury when said chamber is in a substantially horizontal position.

References Cited UNITED STATES PATENTS 7/1931 Mailey 2OO152 9/1937 Coleman 20()61.47

US. Cl. X.R. 

